A brake control apparatus for a vehicle is known in the art, as disclosed, for example, in Japanese Patent Publication No. 2004-161174. According to such a prior art, a pre-charge control is carried out before an actual braking operation of a vehicle driver, in order to apply a braking fluid pressure to a brake pad independently from the actual braking operation of the vehicle driver. As a result of such pre-charge control, a gap between a disc rotor (a non-friction element) and the brake pad (a friction element) is reduced, so that a braking force is immediately applied to vehicle wheels when the braking operation is actually carried out by the vehicle driver.
In the above mentioned prior art, temperature of the disc rotor may be largely increased due to heat generated by the braking operation, and a sliding surface of the disc rotor (which is repeatedly brought into contact with the brake pad) may be inclined due to thermal expansion caused by such temperature increase (hereinafter such inclination is referred to as thermal inclination). When the thermal inclination occurs, a relative distance between the disc rotor and the brake pad will be decreased. Under such a situation, an unintentional vehicle deceleration may occur, if the pre-charge control with a predetermined braking fluid pressure is carried out.
On the other hand, the relative distance between the disc rotor and the brake pad is increased, when the brake pad is worn away, or when the brake pad is pushed back by the disc rotor due to the occurrence of the thermal inclination and then the disc rotor is restored from its thermal inclination to its normal condition due to cool-down of the disc rotor.
Under such a situation, the relative distance (gap) between the disc rotor and the brake pad remains at such an amount larger than a target distance, even when the pre-charge control with the predetermined braking fluid pressure is carried out. As a result, the braking force may not be immediately applied to the vehicle wheels when the braking operation is actually carried out by the vehicle driver.